I don't think it would work on a kite without tip battens. You probably need the stiff fibergalss/carbon battens, instead of inflatable stip struts to support the tension of the back lines through those rings... then again I have't tried it

Looking at the pics of the bar and the pic above I suspect that if you only depower a little, the kite acts like a normal kite and the front lines stay close to the front wingtip. If you depower a lot however you get the scene on the right. This may be why Windwing redesigned the bar so that it has a lot of depower available, and adjustable, on the depower loop. It is clear now why the leash has been moved to the front lines as well.

Also, it appears that when the kite is depowered in this manner it's 'natural postion' is at the edge on the window, not downwind (as with a 5th line system).

Q. With the front line load ending up directly on the leading edge casing at the strut junction when the kite is fully depowered.... Will the casing handle the stress/ deformation??? Has Windwing added substantial reinforcements in this area.. They've taken the front line load off the heavily reinforced normal front wingtip connection point and moved it up to a higher connection point on the leading edge casing.... I would think this would over-stress this area unless also heavily reinforced.....
I don't like the idea of passing the front lines through a fairlead or ring because the added frictional wear on the front lines then becomes a danger .....
Heavily loaded front lines sliding through any form of friction inducing ring scares me..... I kringe whenever I have to self land using the front line safety ring ..
In a freak accident, a broken line could be a killer too...
I'd like to see more pictures and test results. Perhaps this system will be truely revolutionary...

Watching the video I'm impressed... you drop the bar, the kite depowers and keeps flying at the edge of the window and slowly drops down. Pick up the bar and the kite starts flying powered again. Seems like the most gentle form of depower seen yet. Also like SQ said it should help relaunch as there will be more tension towards the middle of the kite.

Also looks like the Windwing kites have inflatable end battens, so there must not be too much pressure on the tips.

I wonder how much front line length is required to activate the system? Do you need to use the Wingwing bar with the pulley?